The most common cause for a toilet stoppage is toilet paper. And it’s worth noting that a more expensive toilet will have fewer clog issues than the builder's or big box store, "Specials". If you have a problem toilet, your choices are to either keep a plunger close by or to replace the problem toilet with a more reliable one. They do cost more but this is really one item you don’t want to scrimp on.
If the plunger fails to do the trick, call Rooter n Drains. One of our highly trained professionals will send a mechanical snake into the bowl and either clear it out or retrieve whatever object may be in there. If you have little ones, it’s common to find small toys etc. lodged in the bowl.